Electrochemical cells are desirable for various applications, particularly when operated as fuel cells. Fuel cells have been proposed for many applications including electrical vehicular power plants to replace internal combustion engines. One fuel cell design uses a solid polymer electrolyte (SPE) membrane or proton exchange membrane (PEM), to provide ion exchange between the cathode and anode. Gaseous and liquid fuels are useable within fuel cells. Examples include hydrogen and methanol, and hydrogen is favored. Hydrogen is supplied to the fuel cell's anode. Oxygen (as air) is the cell oxidant and is supplied to the cell's cathode. The electrodes are formed of porous conductive materials, such as woven graphite, graphitized sheets, or carbon paper to enable the fuel to disperse over the surface of the membrane facing the fuel supply electrode. A typical fuel cell is described in U.S. Pat. No. 5,272,017 and U.S. Pat. No. 5,316,871 (Swathirajan et al.).
Important aspects of a fuel cell include reaction surfaces where electrochemical reactions take place, catalysts which catalyze such reaction, ion conductive media, and mass transport media. The cost of power produced by a fuel cell is in part dependent on the cost of the catalyst. The cost of power produced by a fuel cell is significantly greater than competitive power generation alternatives, partly because of relatively poor utilization of precious metal catalysts in conventional electrodes. However, power produced from hydrogen-based fuel cells is desirable because hydrogen is environmentally acceptable and hydrogen fuel cells are efficient. Therefore, it is desirable to improve the catalyst utilization in fuel cell assemblies to render fuel cells more attractive for power generation. It is also desirable to improve reactant gas diffusion and movement of product water in the fuel cell.